upd7566a Renesas Electronics Corporation., upd7566a Datasheet - Page 25

• Manufacturer Part Number: upd7566a
• Description: 4-bit Single-chip Microcomputer
• Manufacturer: Renesas Electronics Corporation.

4.
pin:
4.1
or reinitialize the contents for the registers by program.
Caution When the RESET signal is used to released the standby mode, the contents of the data memory do
The microcomputer is reset and initialized as follows, when an active-high RESET signal is input to the RESET
When the RESET signal is removed, the program is executed starting from address 000H. However, initialize
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
RESET FUNCTION
INITIALIZATION
The program counter (PC9 to PC0) is cleared to 0.
The skip flags (SK1 and SK0) for the program status word are reset to 0.
The count register for the timer/event counter is cleared to 00H.
The clock control circuit is initialized as follows:
• Clock mode register (bits CM2 and 1) = 0
• Prescalers 1, 2, and 3 = 0
The SM3 flag is reset to 0, disabling the external test input (INT0).
The test request flags (INTT RQF and INT0 RQF) are reset to 0.
The contents of the data memory and the following registers will become undefined.
Stack pointer (SP)
Accumulator (A)
Carry flag (C)
General-purpose registers (H and L)
Output latches for ports
The output buffers for all the ports are turned off and enter the output high-impedance state.
The I/O ports are set in the input mode.
not become undefined, but are retained.
CP = CL x
256
1
PD7566A, 7566A(A)
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